The present invention relates to a new developing agent for a silver halide color photographic material, a liquid composition containing the developing agent for processing and a process for forming a color image with the processing liquid composition. In particular, the present invention relates to a developing agent for a silver halide color photographic material suitable for processing ordinary color photographs and having an improved light fastness of yellow dye, a processing liquid composition containing the developing agent and a process for forming a color image with the processing liquid.
Various p-phenylenediamine compounds, particularly N,N-dialkyl-substituted p-phenylenediamine compounds, were proposed as color developing agents to be contained in a color developer. For example, alkyl groups at N-position proposed heretofore include N-hydroxyalkyl groups described in U.S. Pat. No. 2,108,243 and British Patent No. 807,899, N-sulfonamidoalkyl groups described in U.S. Pat. Nos. 2,193,015, 2,552,240 and 2,566,271, N-sulfamoylalkyl groups described in U.S. Pat. No. 2,193,015, N-acylaminoalkyl groups described in U.S. Pat. Nos. 2,552,242 and 2,592,363, N-quaternary ammoniumalkyl groups described in British Patent No. 539,937, N-alkyl groups having a phosphorus atom as their substituent described in British Patent No. 539,395, N-acylalkyl groups described in U.S. Pat. No. 2,374,337, N-alkoxyalkyl groups described in U.S. Pat. No. 2,603,656, Japanese Patent Unexamined Published Application (hereinafter referred to as "J. P. KOKAI") Nos. Sho 47-11534 and Sho 47-11535, Japanese Patent Publication for Opposition Purpose (hereinafter referred to as "J. P. KOKOKU") Nos. Sho 54-16860, Sho 58-14670 and Sho 58-23618, N-sulfoalkyl groups described in British Patent No. 811,679 and N-aralkyl groups described in U.S. Pat. No. 2,716,132. The substituents of the benzene nucleus include, for example, nuclear alkoxyl groups described in U.S. Pat. Nos. 2,304,953, 2,548,574, 2,552,240 and 2,592,364, nuclear acylaminosulfonamide groups described in U.S. Pat. Nos. 2,350,109 and 2,449,919, nuclear acylaminoalkylsulfonamidoalkyl groups described in U.S. Pat. Nos. 2,552,241, 2,556,271 and 2,592,364, nuclear amino group described in U.S. Pat. Nos. 2,570,116, 2,575,027 and 2,652,331, and nuclear thiosulfonic acid groups described in British Patent No. 872,683. As for the use of compounds analogous to p-phenylenediamine as the color developing agents, tetrahydroquinolines and dihydroindoles are described in U.S. Pat. Nos. 2,196,739 and 2,566,259, N-(p-aminophenyl)hexamethyleneimines are described in U.S. Pat. No. 2,612,500 and 9-aminodurolidines are described in U.S. Pat. No. 2,707,681.
Among various photographic properties required of color developing agents, three properties that the developing activity is high, that hue of the dye formed by the coloring reaction with a coupler is suitable for the color reproduction and that the dye is stable to heat and light are indispensable. However, it is a difficult technical problem to satisfy all of the three requirements by improving the color developing agent. Investigations have been made in this technical field on the improvement of the developing activity by improving mainly the silver halide emulsion and improvement of the hue and fastness of the resulting dye by improving the coupler and using a fading inhibitor.